Toyota Sienna Service Manual: Short to B+ in Front Pretensioner Squib LH Circuit

DTC B0138/72 Short to B+ in Front Pretensioner Squib LH Circuit

DESCRIPTION

The front pretensioner squib LH circuit consists of the center airbag sensor assembly and the front seat outer belt assembly LH.

This circuit instructs the SRS to deploy when deployment conditions are met.

DTC B0138/72 is recorded when a short to B+ is detected in the front pretensioner squib LH circuit.

INSPECTION PROCEDURE

HINT:

•  Perform the simulation method by selecting the "check mode" (signal check) with the intelligent tester (8).
•  After selecting the "check mode" (signal check), perform the simulation method by wiggling each connector of the airbag system or driving the vehicle on a city or rough road

1 CHECK FRONT SEAT OUTER BELT ASSEMBLY LH (FRONT PRETENSIONER SQUIB LH)

1. Turn the ignition switch to the LOCK position.
2.  Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3.  Disconnect the connectors from the front seat outer belt assembly LH.
4.  Connect the white wire side of SST (resistance 2.1 Ω) to the floor wire.

CAUTION: Never connect a tester to the front seat outer belt assembly LH (front pretensioner squib LH) for measurement, as this may lead to a serious injury due to airbag deployment.

SST 09843-18060

5.  Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.
6.  Turn the ignition switch to the ON position, and wait for at least 60 seconds.
7.  Clear the DTCs stored in memory (5).
8.  Turn the ignition switch to the LOCK position.
9.  Turn the ignition switch to the ON position, and wait for at least 60 seconds.
10.  Check the DTCs (5).

OK: DTC B0138/72 is not output. HINT: Codes other than DTC B0138/72 may be output at this time, but they are not related to this check.

Go to step 2

REPLACE FRONT SEAT OUTER BELT ASSEMBLY LH

2 CHECK FLOOR WIRE (FRONT PRETENSIONER SQUIB LH CIRCUIT)

1. Turn the ignition switch to the LOCK position.
2.  Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3.  Disconnect the SST (resistance 2.1 Ω) from the floor wire.
4.  Disconnect the connector from the center airbag sensor assembly.
5.  Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.
6.  Turn the ignition switch to the ON position.
7.  Measure the voltage according to the value(s) in the table below.

Standard voltage

REPAIR OR REPLACE FLOOR WIRE

3 CHECK CENTER AIRBAG SENSOR ASSEMBLY

1. Turn the ignition switch to the LOCK position.
2.  Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3.  Connect the connectors to the front seat outer belt assembly LH and the center airbag sensor assembly.
4.  Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.
5.  Turn the ignition switch to the ON position, and wait for at least 60 seconds.
6.  Clear the DTCs stored in memory (5).
7.  Turn the ignition switch to the LOCK position.
8.  Turn the ignition switch to the ON position, and wait for at least 60 seconds.
9.  Check the DTCs (5).

OK: DTC B0138/72 is not output.

HINT: Codes other than DTC B0138/72 may be output at this time, but they are not related to this check.

REPLACE CENTER AIRBAG SENSOR ASSEMBLY

USE SIMULATION METHOD TO CHECK